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Discussion Starter · #1 ·
Ok, first I want to say that I have read the thread entitled "Full Boost in all gears", but I didnt seem to really find the answer to my question, so I am posting to see if maybe somebody else has encounter this w/ the same gauge or knows the real answer. My car is an 02 and is also stock except for a drop in K&N air filter.

This weekend, I finally installed my mechanical Autometer Sport Comp boost gauge, and now I've never had a bigger headache.

Heres what I did, followed by results: Instead of cutting the line of the BOV I bought some new vacuum hose (same size and all), cut a small amount, connected it to the BOV and to the 1/4 T, of course connected the hose to the other side. I took a 1/8 adapter, put it on the T and put the pressure hose in which fit nice and snug and taped it up to prevent any leaks. I ran the line along the rubber hoses, in through the firewall, under the dash to the A-pillar and to the gauge.

Now I put thread sealent on the screws, put everything together as per the instructions and fired my girl up. I am now sittin at a -20/-18 vacuum and when I gun it in first the gauge leaps up to 12-13 psi or so. However, when I accelerate fast, but dont gun it it goes to 7-8psi. 2nd gear always runs up to 12 or so PSI, but the rest of the gears are the standard 14.5 psi. Now at first I thought there was somethin wrong w/ the gauge, so I took it apart, but it back together again and blah blah blah, but got the same dang results. Amusingly enough, when the blower goes on or when I have the AC on the vacuum drops to -15 or so and from what I saw, I think the gauge reads more accurately.

I've never had a boost gauge in, but I know somethin is really wrong to be reading such low vacuum and funky levels in 1st and 2nd. I monitored it today and noticed when I hit 3,100RPM and could hear the turbo spinning, the gauge read 0psi...which to me sounds right (but what the f*@k do I know right? :D ).

So what the hell is going on here? Dark Rex and I have been puttin our heads together and cant come up w/ anything and it doesnt feel like I'm runnin at a higher boost level b/c I notice a change in speed/performance from 2nd to 3rd. Anybody have this problem w/ an Autometer? Do I need to piss on the gauge and throw it in the trash? What on gods green earth have I done!?!?!?!?! :mad:

Thanks in advance and I look forward to your input...but no arguments between hippies and average joe guys in the thread please ;) :D


Frustrated and pissed that I cant get this easy mod to work
-Lt. Boom Stick
 

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Man, don't feel bad... I still cant get my VDO gauge to quit leaking.. the brass pieces keep getting threaded.. I felt like such a numb nuts installing it... I made the mistake of getting one that didn't show vacuum and just showed 0-30 PSI... DUMB JUSTIN!!! I think I will be remedying this mistake soon enough though.
 

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I dunno man, it doesn't quite sound wrong to me?:confused:
 

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Discussion Starter · #4 ·
I guess whats throwing me for a loop is that when I gun it in first, it leaps up well past 9psi (unless I do a faster acceleration then it resides at 8-9 or so), and in second she always leaps up to twelve. I have also heard that vacuum is supposed to be at -13 or so and mine is at -20? WTF Autometer! U just made my sheet list

:D
 

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Thinking Man's Engine
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Frank @ Autospeed had the same exact problem one time.

A new boost gauge was the answer as the original one he had was defective.
 

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Uhhh... Relax. Nothing is wrong. All is normal/fine. If your car is pretty much stock, then that's exactly how it's supposed to behave; about 20 inches of mercury (in Hg) at idle. 14.5 pounds per inch (psi) at wide open throttle in 3rd, 4th and 5th gears is normal, as well as the lower than 14.5 psi for 1st and 2nd. Don't mess with it too much or YOU WILL break something. Good luck.

tk
 

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Discussion Starter · #7 ·
Fine, 3rd-5th r cool. I'm hitting 14.5 psi, which is right on the head and when I hear the turbo spools the needle is at zero.

BUT why oh why, am I gettin full boost in 1st and 2nd when I gun the car (pedal to the metal)? And why when I do a fast acceleration (not a launch or fast gun off the line) am I gettin 9 in first (which I know is right where its supposed to be) and in second gettin 12-13, sometimes even full boost?

And I quote Towlie "Oh man I have no idea whats going on...." :confused:

Thanks for the help...
 

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Stock boost reaches a maximum of 14.5psi, and not very often. Without a MBC, or EBC you won't hold steady at those levels. You'll see 9-12psi pretty often.
 

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Is it possible for a mechanical gauge to work sometimes and not at others?

I'm sure it's possible but unlikely.

Sounds to me your gauge is working fine and that your car is boosting higher than the "norm" at 1st and 2nd.

If you need more proof, try another gauge.

Hg.
 

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In the stock subaru ecu, it holds (or attempts to hold) the boost at only 5 psi unless its at open throttle then it lets it acheive full boost.
 

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Discussion Starter · #11 ·
BoostedBoxer said:
In the stock subaru ecu, it holds (or attempts to hold) the boost at only 5 psi unless its at open throttle then it lets it acheive full boost.
By open throttle you mean, punchin the sh*+ out of it right? If thats the case then I'm in the money b/c thats the only time it jumps to full boost.

Thanks for your help guys, I was beginning to think I was defeated by a frickin inanimate object. :D
 

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What did you guys use to T off the BOV hose? one of those plastic garden Ts? Or what? anyone got a picture?
 

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BoostedBoxer said:
In the stock subaru ecu, it holds (or attempts to hold) the boost at only 5 psi unless its at open throttle then it lets it acheive full boost.
that's not entirely true. the stock ECU controls fuel and boost based on throttle position. 33% TPS = 1/3 fuel and boost, 66% TPS = 2/3 air and fuel, and WOT = full boost and fuel. this is the whole reason for the PTFB scare.

the ECU's measures are different based on TP as well (open/closed loop) so your readings could change for the first third of throttle epending on atmospheric conditions, but should be the same after that b/c the ECU will adjust for the open loop readings. only altitude will not be affected by this b/c no matter the open loop readings, the turbo w/ not be able to make full boost once the air gets too thin.

dR
 

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mine didn't come with one... i have a ghetto rigged looking brass pressure T that im using currently... but I'd like to make it a MUCH cleaner install however... I live in a small town and dont have much of a choice on where to get things... so i have to find an alternative.
 
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